Firstly I'm no carpenter, but have recently been doing the same for window frames....
I can recommend the following, for the morices make sure you have decent chisels (of appropriate sizes), when i say decent, the most important is SHARP (blunt chisels are neither use, nor ornament)!!!, Stanley do a good set which includes a guide and oils stone. Irwin also do some good ones, both in sets and individually. B&Q (Magnessun, or something like that), do small sets at a resonable price.
I would also recommend a morticing gauge to mark out both the mortices and the tenons. Also a sharp tenon saw, and don't force it when cutting, keep it smooth, that way it won't twist or go off line.
Tenons seem to work best if they're 1/3 the thinkness of the timber.
if you always mark from the same side (usually the front) - i find the finnished joint looks better, and morelikely to be flush when put together.
When chiselling out the mortices, mark accross the grain with a stanley knife so it doesn't split the grain and splinter. if the mortices are of a decent size you can use a spade/flat bit to drill out most of the waste - which males the chiselling easier. If you carefully chisel down about 5mm, starting from the middle working out towards the line you should also get a neater edge to the mortice.
Don't be tempteed to take out too much at once, you'll find it longer, but neater. If you end up with too looser fit cut some small wedges to tighten it up.
I found to start also that spending an afternoon butchering scrap wood for target practice was very helpful and
cheaper in the longrun
I'm sure there are loads of people here who can offer more experience, and (hopefully) would agree
I guess I've left myself open to being put right here, but am more than happy to be corrected on the basis of improoving my own skills
